This month, the Lumia 630 became the first handset designed around Windows Phone 8.1 to go on sale, most recently being rolled out to the United Kingdom. At its launch, Microsoft UK described the 630 as the "new entry-level Windows Phone 8.1 device", but also said that the older Lumia 520 - which is cheaper, but launched with WP8 - will continue to be sold for some time to come.

The Lumia 630 is the most affordable Windows Phone 8.1 device we've seen... so far

That may well be the case for the Brits, but it seems that Microsoft's recently-acquired Nokia division could be planning a WP8.1 successor to the 520 that would sit below the 630 in its range outside of the UK. According to everyone's favourite leaker @evleaks, that handset is the Lumia 530, and it's destined for T-Mobile USA.

It is unclear whether or not the 530 - known also by its development codename 'Rise' - will be exclusive to T-Mobile, or if the device will also make it to other carriers in the United States, or other markets across the globe.

T-Mobile has sold exclusive Windows Phone models before. It previously offered the mid-range Lumia 810, although that device was withdrawn from sale after less than seven months, and the carrier no longer supports it. It continues to sell the ultra-affordable Lumia 521 (a variant of the 520), which the 530 looks set to replace.